Objective Assessing the therapeutic effects of a combination of intra-articular and intra-osseous infiltrations of platelet-rich plasma (PRP) to treat severe knee osteoarthritis (KOA) using intra-articular injections of PRP as the control group. Design In this observational study, 60 patients suffering from severe KOA were treated with intra-articular infiltrations of PRP (IA group) or with a combination of intra-osseous and intra-articular infiltrations of PRP (IO group). Both groups were matched for sex, age, body mass index, and radiographic severity (III and IV degree according to Ahlbäck scale). Clinical outcome was evaluated at 2, 6, and 12 months, using the Knee injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaires. Results At 2, 6 and 12 months after treatment, IO group had a significant improvement in all KOOS and WOMAC subscales ( P < 0.05). On the contrary, patients of the IA group did not improve in any of the scores. Sixteen out of 30 IO group patients showed minimal clinically important improvement (MCII) whereas 8 out of 30 IA group patients showed this response at 6 months (26.7%; 95% CI -0.4 to 49.9; P = 0.037). At 12 months, 14 patients of IO group and 5 patients of the IA group showed MCII (30%; 95% CI 4.3 to 51.9; P = 0.013). No differences between groups were observed at 2 months. Conclusions PRP intra-articular injections in severe KOA were not effective and did not provide any benefit. Combination of intra-articular and intra-osseous infiltrations of PRP was not clinically superior at 2 months, but it showed superior clinical outcomes at 6 and 12 months when compared with intra-articular injections of PRP.

Versatile systems allowing the preparation of different plasma formulations, such as PPP, PRP, or L-PRP, can help refine clinical applications by taking advantage of their different biological properties.

Knee osteoarthritis (OA) is a degenerative process that slowly destroys the joints producing pain and loss of function, and diminishes the quality of life. Current treatments alleviate this symptomatology but do not stop the disease, being total knee arthroplasty the only definitive solution. Among the emerging treatments, Platelet-Rich Plasma (PRP) has shown promising results in the treatment of OA. However, to improve its effectiveness, it is necessary to approach this pathology targeting the whole joint, not only the cartilage, but including other tissues such as subchondral bone. The pathological processes that occur in the subchondral bone have influence of the cartilage loss, aggravating the disease. The combination of intraarticular infiltrations with intraosseous infiltrations regulates the biological processes of the tissues, reducing the inflammatory environment and modulating the overexpression of biomolecules that generate an aberrant cellular behavior. Although the first clinical results using this technique are promising, further research and developing adequate protocols are necessary to achieve good clinical results.

Platelet-rich plasma (PRP) is a biological therapy that uses the patient's own blood to obtain products with a higher platelet concentration than in blood. It provides a transient fibrin scaffold as a controlled drug delivery system of growth factors suitable for regenerative medicine. PRP has been used as medical strategy to treat diverse types of injuries in the field of orthopedics, including peripheral nerve lesions. In vitro and in vivo studies showed the neuroprotective, neurogenic and neuroinflammatory modulator effect of PRP. In addition, it has been demonstrated clinically that PRP infiltrations improve clinical symptoms and enhance the sensory and motor functional nerve muscle unit recovery. Potential effects of PRP could be applied in treatments for neuropathies, as conservative treatment by means of nerve ultrasound-guided infiltrations or as biological adjuvant during surgery.

Platelet-rich plasma (PRP) is a biologic therapy that promotes healing responses across multiple medical fields, including the central nervous system (CNS). The efficacy of this therapy depends on several factors such as the donor’s health status and age. This work aims to prove the effect of PRP on cellular models of the CNS, considering the differences between PRP from young and elderly donors. Two different PRP pools were prepared from donors 65‒85 and 20‒25 years old. The cellular and molecular composition of both PRPs were analyzed. Subsequently, the cellular response was evaluated in CNS in vitro models, studying proliferation, neurogenesis, synaptogenesis, and inflammation. While no differences in the cellular composition of PRPs were found, the molecular composition of the Young PRP showed lower levels of inflammatory molecules such as CCL-11, as well as the presence of other factors not found in Aged PRP (GDF-11). Although both PRPs had effects in terms of reducing neural progenitor cell apoptosis, stabilizing neuronal synapses, and decreasing inflammation in the microglia, the effect of the Young PRP was more pronounced. In conclusion, the molecular composition of the PRP, conditioned by the age of the donors, affects the magnitude of the biological response.

In some surgical techniques like femoral derotation osteotomy, accuracy is a key factor that often is not optimal because of the lack of appropriate technology. 3D printing is emerging in many professional areas and its use in the medical field may enhance the results of certain surgeries. This case describes a patient who underwent an intramedullary nail fixation to treat a femoral shaft fracture. After nine months, the patient presented hip pain and "in toe" walking caused by a malrotation produced during the surgery. To address the consequent femoral derotation osteotomy, 3D technology was used throughout the whole process. A 3D model of the patient's femur was created to conduct a real and accuracy assessment of femoral anteversion. Then, a customized surgical guide was designed and printed to ensure the proper alignment during surgery. Given the success of this surgery, 3D printing can be considered a quick and inexpensive tool to improve surgical results.

Platelet-rich plasma (PRP) products can be described as any autologous blood platelet concentrate within a plasma suspension. PRP products include plasma and twofold or greater increases in platelet concentrations above baseline levels. The injection of activated PRP in its liquid formulation delivers growth factors locally and simultaneously mimics and amplifies the spontaneous healing response in injured areas and in special cell niches, which would otherwise be inaccessible. This in situ generated transient threedimensional scaffold will gradually release growth factors and maintain their concentration at the site of the scaffold formation. The combination of liquid PRP with surgical techniques in orthopaedic surgery allows a wide range of therapeutic strategies in the management of injuries in the field of orthopaedics and sports medicine. The use of different therapeutic elements, including PRP as biological stimuli and rehabilitation and physiotherapy treatments as mechanical stimuli, provides extremely favourable synergies that will help fulfil the physician's objective, to stop the progression of disease and to improve function in the shortest period of time

Platelet-Rich Plasma (PRP) is a biologic therapy that uses the patient's own blood to obtain products with a higher platelet concentration than in blood. This technology provides a controlled drug delivery system of growth factors suitable for regenerative medicine. The biological effects of PRP mimic and influence biological processes such as inflammation, analgesia, and cell stimulation, providing this therapy with promising therapeutic potential. All these processes participate in maintenance, correct function, and homeostasis of the joint, where all tissues are involved. Alterations in one joint element have impact on the rest, outstanding the cellular and molecular interaction between the cartilage and subchondral bone. Therefore, the joint is an optimal therapeutic target for PRP therapy, which favors biological environment for joint repair. This chapter collects the basic concepts of joint function and the biological processes that participate in its degeneration, the definition and obtention of PRP, as well as its therapeutic potential and clinical translation.